A reconciliation of the opening and closing balances of the fair value of scheme assets is set out below:

Scheme assets held by all defined benefit schemes operated by the Group at December 31 comprise:

1 Includes employer contributions to APS of €109 million (2016: €112 million) and to NAPS of €748 million (2016: €763 million), of which deficit funding payments represented €104 million for APS (2016: €106 million) and €516 million for NAPS (2016: €638 million).

For both APS and NAPS, the Trustee has ultimate responsibility for decision making on investments matters, including the asset-liability matching strategy. The latter is a form of investing designed to match the movement in pension plan assets with the movement in the projected benefit obligation over time. The Trustees’ investment committee adopts an annual business plan which sets out investment objectives and work required to achieve these objectives. The committee also deals with the monitoring of performance and activities, including work on developing the strategic benchmark to improve the risk return profile of the scheme where possible, as well as having a trigger based dynamic governance process to be able to take advantage of opportunities as they arise. The investment committee reviews the existing investment restrictions, performance benchmarks and targets, as well as continuing to develop the de-risking and liability hedging portfolio.

Both schemes use derivative instruments for investment purposes and to manage exposures to financial risks, such as interest rate, foreign exchange and liquidity risks arising in the normal course of business. Exposure to interest rate risk is managed through the use of Inflation-Linked Swap contracts. Foreign exchange forward contracts are entered into to mitigate the risk of currency fluctuations. For NAPS, a strategy exists to provide protection against the equity market downside risk by reducing some of the upside participation.

Scheme assets held by all defined benefit schemes operated by the Group at December 31 comprise:

All equities and bonds have quoted prices in active markets.

For APS and NAPS, the composition of the scheme assets is:

The strategic benchmark for asset allocations differentiates between ‘return seeking assets’ and ‘liability matching assets’. Given the respective maturity of each scheme, the proportion for APS and NAPS vary. At December 31, 2017, the benchmark for APS, expressed as a percentage of the assets excluding the insurance contract, was 9.5 per cent (2016: 19 per cent) in return seeking assets and 90.5 per cent (2016: 81 per cent) in liability matching investments; and for NAPS the benchmark was 65 per cent (2016: 68 per cent) in return seeking assets and 35 per cent (2016: 32 per cent) in liability matching investments. Bandwidths are set around these strategic benchmarks that allow for tactical asset allocation decisions, providing parameters for the investment committee and its investment managers to work within.

In addition to this, APS has an insurance contract with Rothesay Life which covers 24 per cent (2016: 24 per cent) of the pensioner liabilities for an agreed list of members. The insurance contract is based on future increases to pensions in line with inflation and will match future obligations on that basis for that part of the scheme. The insurance contract can only be used to pay or fund employee benefits under the scheme. With effect from June 2010, the Trustee of APS also secured a longevity swap contract with Rothesay Life, which covers 20 per cent (2016: 20 per cent) of the pensioner liabilities for the same members covered by the insurance contract above. The value of the contract is based on the difference between the value of the payments expected to be received under this contract and the pensions payable by the scheme under the contract. During 2017, the Trustee of APS secured two additional longevity swap contracts, one with Canada Life and one with Partner Reinsurance covering 13 per cent and 8 per cent respectively of the pensioner liabilities as at January 1, 2017 (the commencement date of the contracts). The principal increases to pensions in payment under the contract are based on RPI inflation.